A self-oscillating DCM is disclosed comprising two inductors that charge
and discharge 180 degrees out of phase such that the charging inductor is
conducting an upward ramping current and the discharging inductor is
conducting a downward ramping current. A load receives the upward and
downward ramping currents, which combine to create a constant current.
The current source that powers the DCM is current limited so as to output
a maximum direct current of I.sub.IN. A relatively small capacitor is
connected across the input terminals of the DCM and allows the inductors
to ramp up to a peak current of 2*I.sub.IN. Since the current source only
supplies the ramping current to one of the inductors at a time up to
2*I.sub.IN, and the average current conducted by each inductor is
I.sub.IN, the current supplied by the current source is a constant
I.sub.IN. However, since the inductors simultaneously supply two
oppositely ramping currents to the load, the load current is a constant
current equal to 2*I.sub.IN. So the DCM doubles the supply current and
halves the average input voltage.